Scatterplots

With ggExtra

p7 <- ggplot(all, aes(x = percentile_2016, y = Current_Asthma2018, size = totalpopE, alpha = 1/10, color = county)) +
  geom_point() +
  labs(x = "PM2.5 Percentile, 2016", y = "Percent with Asthma")
ggMarginal(p7, type = "histogram")

A few adjustments

# adjustments
p7 <- ggplot(all, aes(x = percentile_2016, y = Current_Asthma2018, size = totalpopE, alpha = 1/10, color = county)) +
  geom_point() +
  labs(x = "PM2.5 Percentile, 2016", y = "Percent with Asthma") +
  guides(size = "none", alpha = "none") +
  theme(legend.position = "bottom")
ggMarginal(p7, type = "histogram")

ggExtra not integrated with ggplotly

ggplotly(p7)

With plot_ly

# upper left panel
xhist <- plot_ly(data = all, x = ~percentile_2016, type = 'histogram', 
                 nbinsx = 20, alpha =.75, color = I("grey")) 

# lower left panel
xyscatter <- plot_ly(data = all, 
                     x = ~percentile_2016, 
                     y = ~Current_Asthma2018, 
                     type = 'scatter',
                     mode = 'markers',
                     marker = list(size = ~totalpopE, sizeref = 20, sizemode = 'area'),
                     color = ~county, 
                     colors = "Dark2", 
                     alpha = .75,
                     hoverinfo = 'text',
                     text = ~paste('County:', county, '<br>Population:', totalpopE,
                      '<br>PM2.5 Percentile:', percentile_2016,
                      '<br>Percent with Asthma:', Current_Asthma2018)) %>% 
  layout(xaxis = list(title = "PM2.5 Percentile, 2016"),
         yaxis = list(title = "Percent with Asthma"),
         legend = list(orientation = "h", x = 0, y = -0.2))

# lower right panel
yhist <- plot_ly(data = all, y = ~Current_Asthma2018, type = 'histogram', 
                 nbinsx = 20, alpha = .75, color = I("grey")) 

Pieces were built separately and assembled with subplot()

# plotly_empty fills in upper right panel with nothing
subplot(xhist, plotly_empty(), xyscatter, yhist,
        nrows = 2, heights = c(.2, .8), widths = c(.8,.2), margin = 0,
        shareX = TRUE, shareY = TRUE) %>% 
  style(showlegend = FALSE, traces = c(1,9)) %>% # remove hist symbols from legend  
  layout(xaxis = list(showgrid = TRUE),
         yaxis2 = list(showgrid = TRUE))

How to get the primary box/edges around the scatterplot?